Gray Code

A Gray code is a list of all 2^n bit strings of length n, where any two successive strings differ in exactly one bit (i.e., their Hamming distance is one). Your task is to create a Gray code for a given length n. Input The only input line has an integer n. Output Print 2^n lines that describe the Gray code. You can print any valid solution. Constraints - 1 \le n \le 16 Example Input: 2